英语翻译

英语翻译
翻译一段有关计算机方面的英文文本
Abstract.In extremely heterogeneous and distributed systems,like Grid envi-ronments,it is quite difficult to provide quality of service (QoS).In addition,the dynamic behaviour of the resources makes the time needed to complete theexe-cution of a job highly variable.So,fulfilling the user QoS requirements in a Grid is still an open issue.The main aim of this work is to provide QoS in Grid envi-ronments through network-aware job scheduling in advance.This paper presents a technique to manage idle/busy periods of resources using red-black trees which considers the network as a first level resource.Besides,noa prioriknowledge on the duration of jobs is required,as opposed to other works.A performance evaluation using a real testbed is presented which illustrates the efficiency of this approach to meet the QoS requirements of users,and highlights the importance of taking the network into account when predicting the duration of jobs.